G9a is not required for the transcriptional repression of selected early embryonic genes during retinoic acid (RA)-induced differentiation. The indicated mESC lines were untreated (0) or treated with 1 μM RA for 2, 4 or 8 days. (A) Immunoblots were used to determine G9a, Oct3/4 and GAPDH (loading control) protein levels in whole cell extracts. (B) Graph shows the messenger (mRNA) levels for the indicated genes using RT-qPCR analysis with Ubiquitin C (UBC) as the normalization control. All mRNA levels are normalized to the TT2 0 RA sample. Results shown are mean ± SD for three PCR reactions performed on the same cDNA sample and are representative of three independent experiments.